APPLICANT'S ABSTRACT: Spirituality has been an integral aspect of Alcoholics Anonymous (AA) since its founding. While researchers have shown greater interest in AA over the past decade, relatively little empirical attention has been placed on spirituality. In recognition of the importance of this topic, the present study was designed to address three primary objectives: (1) To assess the relationship between AA participation (defined as attendance and involvement in AA) to spirituality (defined as sense of life purpose, serenity, and religiosity) over the course of residential treatment for alcoholism and a 6-month posttreatment follow-up period. The tenets of AA reflect spiritual beliefs and spiritual practices, such as the belief and relationship with a higher power, mysticism, and renewal. Thus, it is hypothesized that AA participation will be positively associated with spirituality (e.g., increased AA participation will lead to increases on measures of spirituality). (2) To assess the role of spirituality as a partial mediator of the demonstrated relationship between AA participation and alcohol outcome. Reviews of descriptive and quasi-experimental research on AA's therapeutic effectiveness are modestly positive, in terms of alcohol outcome. The mechanism, or mediation, of the therapeutic effect of AA participation, however, has not been studied. It is hypothesized that spirituality is a partial mediator of the demonstrated effect of AA on posttreatment outcome. (3) To empirically examine, in exploratory fashion, several variables as potential mediators of the proposed relationship between AA participation and spirituality. The variables of interest, selected on the basis of their conceptual relevance to both AA and spirituality, are forgiveness, self- esteem, hope, and the seeking of life purpose.